A cost-effective method for repairing lithium manganese oxide cathode materials and its application.

Abstract

This invention relates to the field of H01M10 / 54 technology, specifically to a method for repairing lithium manganese oxide cathode materials with high cost-effectiveness and its application, comprising at least the following steps: (1) collecting the powder after low-temperature treatment of the cathode sheet of waste lithium manganese oxide batteries and separating it from the foil; (2) sieving and demagnetizing the powder to obtain cathode powder; (3) adding the cathode powder to an inorganic salt solution for stirring and mixing to obtain a mixture; (4) filtering, drying, crushing the mixture and placing it in a saggar for calcination to obtain sintered material; (5) washing and drying the lithium manganese oxide material after crushing, sieving, and demagnetizing the sintered material. By disassembling and processing the recycled batteries to obtain the electrode sheet, and then treating the electrode sheet at low temperature to remove the material from the foil, followed by inorganic salt treatment, its electrochemical performance and processing performance are comparable to those of lithium manganese oxide cathode materials at the same level.

Description

Technical Field

[0001] This invention relates to the field of H01M10 / 54 technology, specifically to a cost-effective method for repairing lithium manganese oxide cathode materials and its application. Background Technology

[0002] Lithium manganese oxide is one of the more promising lithium-ion cathode materials. Compared with traditional cathode materials such as lithium cobalt oxide, lithium manganese oxide has advantages such as abundant resources, low cost, no pollution, good safety, and good rate performance, making it an ideal cathode material for power batteries. With the rapid development of the new energy vehicle industry, the production and sales of lithium manganese oxide batteries have also increased significantly. Of course, this has brought about the problem of waste battery disposal.

[0003] Currently, there are many methods for recycling waste lithium manganese oxide battery materials, but they all have significant drawbacks. A common method involves reacting an acidic solution with lithium manganese oxide in the battery cell, then using alkali precipitation to recover manganese, followed by sodium carbonate precipitation of lithium. For example, Chinese patent application (application number CN111484043A) discloses a comprehensive recycling method for waste lithium manganese oxide and lithium iron phosphate cathode materials. Specifically, it involves steps such as reduction leaching, oxidation leaching, solid-liquid separation, washing, impurity removal, and lithium precipitation to recover the cathode material from waste lithium-ion batteries. However, this method has drawbacks: the initial acid dissolution and impurity removal followed by alkali precipitation results in excessively high costs. Given that manganese is an abundant and inexpensive metal, this method is not economically feasible. Another method involves separating the active material of lithium manganese oxide from the current collector aluminum foil; mixing lithium manganese oxide with ascorbic acid, adjusting the temperature to obtain a dry gel, and sintering the dry gel to obtain a lithium manganese oxide precursor. However, waste batteries contain electrolytes and additives, which this method cannot remove, and the resulting lithium manganese oxide precursor is unlikely to meet battery-grade requirements. The above methods mostly use wet recycling and repair, but the process is complicated, difficult to recycle, and not conducive to recycling. Furthermore, the performance of lithium manganese oxide cathode material is unstable after wet repair, and the recycling cost is high. Summary of the Invention

[0004] To address the aforementioned issues, this invention discloses a cost-effective method for repairing lithium manganese oxide cathode materials. The method involves disassembling and processing recycled batteries to obtain electrode sheets, subjecting the electrode sheets to low-temperature treatment to detach the material from the foil, and then treating them with inorganic salts. The resulting electrochemical and processing properties are comparable to those of lithium manganese oxide cathode materials at the same level.

[0005] This invention provides a cost-effective method for repairing lithium manganese oxide cathode materials, comprising at least the following steps:

[0006] (1) Collect the powder after the positive electrode sheet of the waste lithium manganese oxide battery is separated from the foil after low-temperature treatment;

[0007] (2) The positive electrode powder is obtained by sieving and demagnetizing the powder;

[0008] (3) Add the positive electrode powder to the inorganic salt solution and stir to obtain a mixture;

[0009] (4) After filtering, drying and crushing the mixture, it is placed into a sagger and fired to obtain sintered material.

[0010] (5) The lithium manganese oxide material is obtained by washing and drying after crushing, sieving and demagnetizing the sintered material.

[0011] As a preferred technical solution, the low-temperature treatment in step (1) is carried out at a temperature of 150-300℃ for 1-10 hours. The method provided by this invention obtains the positive electrode sheet by directly dismantling and processing the recycled waste lithium manganese oxide batteries. By controlling the temperature at a low temperature of 150-300℃, the material on the positive electrode sheet is separated from the foil. The process is simple and does not require repeated acid leaching, washing, impurity removal, and alkali leaching steps, ensuring the economic feasibility of recycling.

[0012] As a preferred technical solution, the sieving in step (2) is specifically performed using an ultrasonic vibrating screen. Preferably, the sieve aperture of the ultrasonic vibrating screen is 80-120 mesh.

[0013] As a preferred technical solution, the demagnetization in step (2) is specifically performed using an electromagnetic iron separator.

[0014] As a preferred technical solution, in step (3), the solute concentration in the inorganic salt solution is 1-5 mol / L, and the solvent is deionized water. Preferably, the solute is a metallic inorganic salt and / or a non-metallic inorganic salt; preferably, the solute is at least one selected from K inorganic salt, Mg inorganic salt, P inorganic salt, Ca inorganic salt, Zn inorganic salt, Cr inorganic salt, and Na inorganic salt.

[0015] As a preferred technical solution, the solid content of the mixture in step (3) is 5-60 wt%.

[0016] As a preferred technical solution, the drying temperature in step (4) is 100-150℃ and the drying time is 3-8h.

[0017] As a preferred technical solution, the roasting in step (4) specifically involves: adding a lithium source to the dried and crushed material, mixing it evenly using a high-speed mixer, raising the temperature to 300-800℃ at a controlled heating rate of 0-20℃ / min, holding it at that temperature for 5-20 hours, and then lowering the temperature to 20-30℃ at a controlled rate of 0-20℃ / min. Preferably, the amount of lithium source added is 100-20000ppm. Preferably, the lithium source is a lithium-containing substance, preferably at least one of lithium carbonate, lithium hydroxide, lithium ethoxide, lithium methoxide, lithium isopropoxide, and lithium butoxide.

[0018] The method for repairing lithium manganese oxide cathode material provided in this invention involves mixing the demagnetized cathode powder with inorganic salts, filtering, drying, and then adding lithium salts for subsequent calcination repair. This ensures the effectiveness of the subsequent calcination and improves the performance stability after repair. Furthermore, by controlling the temperature to 300-800℃ for 5-20 hours and then cooling to room temperature, the charge-discharge performance stability of the repaired lithium manganese oxide cathode material is ensured. The electrochemical and processing properties of the repaired material are comparable to those of lithium manganese oxide cathode materials at the same level, with an initial discharge specific capacity of 127.95 mAh / g.

[0019] As a preferred technical solution, the sieve opening for crushing and screening in step (5) is 150-300 mesh.

[0020] As a preferred technical solution, the content of lithium manganese oxide material during water washing in step (5) is 10wt%-40wt%.

[0021] Another aspect of the present invention provides a method for repairing lithium manganese oxide cathode materials with high cost-effectiveness, which is applied to the repair of lithium manganese oxide cathode materials in waste batteries.

[0022] Beneficial effects:

[0023] 1. This invention obtains electrode sheets by disassembling and processing recycled batteries. After the electrode sheets are subjected to low-temperature treatment to remove the material from the foil, and then treated with inorganic salts, their electrochemical performance and processing performance are comparable to those of lithium manganese oxide cathode materials at the same level.

[0024] 2. The method provided by the present invention obtains the positive electrode sheet by directly dismantling the recycled waste lithium manganese oxide battery. The temperature is controlled at a low temperature of 150-300℃ to separate the material on the positive electrode sheet from the foil. The process is simple and does not require repeated acid leaching, washing, impurity removal and alkali leaching steps, ensuring the economic feasibility of recycling.

[0025] 3. The method for repairing lithium manganese oxide cathode material provided in this invention involves mixing the demagnetized cathode powder with inorganic salt, filtering, drying, and then adding lithium salt for subsequent calcination repair, thereby ensuring the subsequent calcination effect and improving the performance stability after repair.

[0026] 4. This invention controls the temperature to 300-800℃ for 5-20 hours and then cools it down to room temperature to ensure the stability of the charge-discharge performance of the repaired lithium manganese oxide cathode material. The electrochemical performance and processing performance of the repaired material are comparable to those of lithium manganese oxide cathode materials at the same level. Attached Figure Description

[0027] Figure 1 This is a scanning electron microscope image of the lithium manganese oxide cathode material after repair in Example 1 of the present invention.

[0028] Figure 2 This is a scanning electron microscope image of the lithium manganese oxide cathode material after repair in Comparative Example 1 of this invention.

[0029] Figure 3 This is a comparison of the charge-discharge curves of the lithium manganese oxide cathode materials after repair in Example 1 and Comparative Example 1 of the present invention. Detailed Implementation

[0030] Example 1

[0031] Embodiment 1 of the present invention provides a cost-effective method for repairing lithium manganese oxide cathode materials, comprising the following steps:

[0032] (1) Collect the powder after the positive electrode sheet of the waste lithium manganese oxide battery is separated from the foil after low-temperature treatment;

[0033] (2) The positive electrode powder is obtained by sieving and demagnetizing the powder;

[0034] (3) Add the positive electrode powder to the inorganic salt solution and stir to obtain a mixture;

[0035] (4) After filtering, drying and crushing the mixture, it is placed into a sagger and fired to obtain sintered material.

[0036] (5) The lithium manganese oxide material is obtained by washing and drying after crushing, sieving and demagnetizing the sintered material.

[0037] The positive electrode plates of the waste lithium manganese oxide batteries come from battery factories.

[0038] In step (1), the low-temperature treatment is carried out at a temperature of 250°C for 3 hours.

[0039] In step (2), the sieving process is specifically carried out using an ultrasonic vibrating screen. The screen aperture of the ultrasonic vibrating screen is 100 mesh.

[0040] In step (2), demagnetization is specifically performed using an electromagnetic separator.

[0041] In step (3), the solute concentration in the inorganic salt solution is 1.5 mol / L, and the solvent is deionized water. The solute is Na₂CO₃.

[0042] The solid content of the mixture in step (3) is 30 wt%.

[0043] The drying temperature in step (4) is 120°C and the drying time is 5 hours.

[0044] The roasting process in step (4) specifically involves adding a lithium source to the dried and crushed material, mixing it evenly using a high-speed mixer, raising the temperature to 700°C at a rate of 10°C / min, holding it at that temperature for 8 hours, and then lowering the temperature to 25°C at a rate of 10°C / min.

[0045] The amount of lithium source added is 500 ppm of Li element, and the lithium source is lithium carbonate.

[0046] In step (5), the sieve used for crushing and screening has a mesh size of 200.

[0047] The content of lithium manganese oxide material during water washing in step (5) is 30 wt%.

[0048] Another aspect of the present invention provides a method for repairing lithium manganese oxide cathode materials with high cost-effectiveness, which is applied to the repair of lithium manganese oxide cathode materials in waste batteries.

[0049] Comparative Example 1

[0050] Comparative Example 1 of the present invention provides a cost-effective method for repairing lithium manganese oxide cathode materials. The specific implementation method is the same as that of Example 1, except that step (3) is not included. The cathode powder obtained after sieving and demagnetizing in step (2) is directly calcined without adding lithium source. The specific details are as follows:

[0051] (1) Collect the powder after the positive electrode sheet of the waste lithium manganese oxide battery is separated from the foil after low-temperature treatment;

[0052] (2) The positive electrode powder is obtained by sieving and demagnetizing the powder;

[0053] (3) The positive electrode powder is placed into a sagger and calcined to obtain sintered material;

[0054] (4) The lithium manganese oxide material is obtained by washing and drying after crushing, sieving and demagnetizing the sintered material.

[0055] Comparative Example 2

[0056] Comparative Example 2 of the present invention provides a cost-effective method for repairing lithium manganese oxide cathode materials. The specific implementation method is the same as that of Comparative Example 1, except that the cathode powder obtained after sieving and demagnetizing in step (2) is mixed with a lithium source and then subjected to calcination treatment, as follows:

[0057] (1) Collect the powder after the positive electrode sheet of the waste lithium manganese oxide battery is separated from the foil after low-temperature treatment;

[0058] (2) The positive electrode powder is obtained by sieving and demagnetizing the powder;

[0059] (3) After the positive electrode powder and lithium source are mixed evenly, they are placed into a saggar and calcined to obtain sintered material.

[0060] (4) The lithium manganese oxide material is obtained by washing and drying after crushing, sieving and demagnetizing the sintered material.

[0061] The roasting process in step (4) specifically involves: adding a lithium source to the crushed material, mixing it evenly using a high-speed mixer, raising the temperature to 700°C at a rate of 10°C / min, holding it at that temperature for 8 hours, and then lowering the temperature to 25°C at a rate of 10°C / min. The lithium source is lithium carbonate, and the amount of lithium source added is 500 ppm of Li element.

[0062] Performance testing methods

[0063] 1. The modified lithium manganese oxide cathode materials of the examples and comparative examples were characterized by scanning electron microscopy. The results are shown in [reference needed]. Figure 1 , Figure 2 .

[0064] 2. The modified lithium manganese oxide cathode materials from the examples and comparative examples were assembled into coin-type CR2032 half-cells and tested at a current density of 0.1C within a voltage range of 3.0V-4.3V. The test results are shown in [reference needed]. Figure 3 As can be seen, the initial discharge specific capacity of Example 1 is 127.95 mAh / g, while that of Comparative Example 1 is 109.50 mAh / g. Example 1 is 18.45 mAh / g higher than Comparative Example 1. The initial discharge specific capacity of Comparative Example 2 is 112.3 mAh / g, while that of Example 1 is 15.65 mAh / g higher than Comparative Example 2.

Claims

1. A cost-effective method for repairing lithium manganese oxide cathode materials, characterized in that, Includes the following steps: (1) Collect the powder after the positive electrode sheet of the waste lithium manganese oxide battery is separated from the foil after low-temperature treatment; (2) The positive electrode powder is obtained by sieving and demagnetizing the powder; (3) Add the positive electrode powder to the inorganic salt solution and stir to obtain a mixture; (4) After filtering, drying and crushing the mixture, it is placed into a sagger and fired to obtain sintered material; (5) The lithium manganese oxide material is obtained by washing and drying after crushing, sieving, and demagnetizing the sintered material; The positive electrode sheets of the waste lithium manganese oxide batteries come from battery factories; In step (1), the low-temperature treatment is performed at 250℃ for 3 hours. In step (2), the sieving process is specifically carried out using an ultrasonic vibrating screen; the screen aperture of the ultrasonic vibrating screen is 100 mesh. In step (2), demagnetization is specifically performed using an electromagnetic separator; In step (3), the solute concentration in the inorganic salt solution is 1.5 mol / L, and the solvent is deionized water; the solute is Na2CO3. The solid content of the mixture in step (3) is 30 wt%; In step (4), the drying temperature is 120℃ and the drying time is 5 hours. In step (4), the roasting process is as follows: lithium source is added to the dried and crushed material, and the mixture is mixed evenly using a high-speed mixer. The temperature is raised to 700°C at a rate of 10°C / min, and kept at that temperature for 8 hours. Then, the temperature is lowered to 25°C at a rate of 10°C / min. The amount of lithium source added is 500 ppm of Li element, and the lithium source is lithium carbonate; In step (5), the sieve used for crushing and screening has a mesh size of 200. In step (5), the content of lithium manganese oxide material during water washing is 30 wt%.

2. The application of a cost-effective method for repairing lithium manganese oxide cathode materials according to claim 1, characterized in that, It is applied to the repair of lithium manganese oxide cathode materials in waste batteries.

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